1. Field of the Invention
This invention relates in one aspect to a method for determining vision defects and for collecting data for correcting vision defects of the eye by interaction of a patient with an examiner and apparatus therefor.
2. Background Information
The primary or traditional method for correcting vision defects, such as, correcting myopia, hyperopia, and astigmatism, comprises selection of and mounting of particular lenses in a spectacle-frame by the physician for a vision test, and the patient establishes his optimal faculty of vision based on the gradation of the test lines of a test image. In accordance with this traditional method, the patient can obtain optimally suited glasses for correction of significant, or approximate or gross, vision defects, but the method substantially may provide only for approximate or rough correction of vision defects.
This classical approach or method has now been replaced by objective metrological methods which are performed without active participation by the patient. Examples include automatic refractometers.
Next to the objective determination of significant vision defects, various topographical apparatus and devices for measuring eye aberrations, such as, aberroscopes or aberrometers, are utilized so as to determine patient-specific cornea topographies and, as well, substantially all wavefront aberrations. On the basis of such metrological data, the patients are treated, for example, by using an excimer laser system, to have specific topographies applied or formed on the cornea of the eye, which topographies are to ensure an optimal faculty of vision (compare: P. Mierdel, H.-E. Krinke, W. Wiegand, M. Kaemmerer, T. Seiler, “Meβplatz zur Bestimmung der monochromatischen Aberration des menschlichen Auges {Test station for the determination of the monochromatic aberration of the human eye}”, OPHTHALMOLOGE, 1997, 94; pages 441–445, SPRINGER VERLAG, 1997).
In these determinations, or measurements or metrological approaches, a double-pass through the optics system of the eye needs to be realized due to technical reasons. The main problem with this method resides therein that the uneven or odd-valent aberrations are determined in a falsified manner. A reduction of the problem with the double-pass method can be obtained, for example, by use of different numerical apertures for the entering and exiting light. Another approach comprises inducing of a fluorescence on the cornea so as to preclude these metrological errors (compare: LASER FOCUS WORLD, April 1999, pages 35–36).
In the methods available in the state of the art, an optical apparatus or system, the eye, which is a rather dynamic system, is precisely measured and corrected, but only in a momentary or snapshot-like manner. This suggests errors, particularly in the desired correction of higher-order aberrations which preclude attainment of an optimal faculty of vision. This is indicated thereby that with the measurements of eye aberrations of eyes actually having the best faculty of vision, occasionally high aberrations are shown, and till this day it is not known with certainty whether a physical correction of the eye actually increases or even worsens the faculty of vision of the eye.
It is further known that aberrations of the human eye can be compensated with the aid of adaptive optics, so as to realize high-resolution images of the cornea for medical investigations (compare: LASER FOCUS WORLD, August 1998, pages 18–22).
A microscope with an adaptive optics is described in German patent publication No. 19 733 193 A1. This publication mentions various wave modulators.
In the paper “Supernormal vision and high-resolution retinal imaging through adaptive optics,” by Liang et al., J. Opt. Soc. Am. A, Vol. 14 (1997), pages 2884–2892, apparatus and method are described with which by way of a wavefront measurement, using a deformable mirror, the feasibility of an adaptive correction of eye aberrations as well as photographic images of the retina is achieved.
U.S. Pat. No. 5,777,719 issued to inventors Williams et al. on Jul. 7, 1998 and entitled “Method and apparatus for improving vision and the resolution of retinal images,” also describes a method and a device for obtaining improved photographic pictures of the retina, with the apparatus, using a deformable mirror, being capable of obtaining corrected pictures of the retina using a CCD-camera.